2. Write the mixed repeating (recurring) decimal number as an improper fraction.
1.628728924 can be written as an improper fraction.
- The numerator is larger than or equal to the denominator.
Set up the first equation.
- Let y equal the decimal number:
y = 1.628728924
Set up the second equation.
- Number of decimal places repeating: 1
Multiply both sides of the first equation by 101 = 10
y = 1.628728924
10 × y = 10 × 1.628728924
10 × y = 16.28728924
Get the same number of decimal places as for y:
10 × y = 16.287289244
Note: 16.287289244 = 16.28728924
Subtract the first equation from the second one.
- Having the same number of decimal places ...
- The repeating pattern drops off by subtracting the two equations.
10 × y - y = 16.287289244 - 1.628728924 ⇒
(10 - 1) × y = 16.287289244 - 1.628728924 ⇒
We now have a new equation:
9 × y = 14.65856032
Solve for y in the new equation.
9 × y = 14.65856032 ⇒
y = 14.65856032/9
Let the result written as a fraction.
Now we can write the number as a fraction.
According to our first equation:
y = 1.628728924
According to our calculations:
y = 14.65856032/9
⇒ 1.628728924 = 14.65856032/9
Get rid of the decimal places in the fraction above.
- Multiply the top and the bottom number by 100,000,000.
- 1 followed by as many 0-s as the number of digits after the decimal point.
1.628728924 = (14.65856032 × 100,000,000)/(9 × 100,000,000)
1.628728924 = 1,465,856,032/900,000,000
3. Reduce (simplify) the fraction above:
1,465,856,032/900,000,000
to the lowest terms, to its simplest equivalent form, irreducible.
To reduce a fraction to the lowest terms divide the numerator and denominator by their greatest (highest) common factor (divisor), GCF.
Factor the numerator and denominator (prime factorization).
1,465,856,032 = 25 × 523 × 87,587
900,000,000 = 28 × 32 × 58
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
GCF (25 × 523 × 87,587; 28 × 32 × 58) = 25
Divide both the numerator and the denominator by their GCF.
1,465,856,032/900,000,000 =
(25 × 523 × 87,587)/(28 × 32 × 58) =
((25 × 523 × 87,587) ÷ 25) / ((28 × 32 × 58) ÷ 25) =
(523 × 87,587)/(23 × 32 × 58) =
45,808,001/28,125,000
4. The fraction is an improper one, rewrite it as a mixed number (mixed fraction):
- A mixed number = an integer number and a proper fraction, of the same sign.
- Example 1: 2 1/5; Example 2: - 1 3/7.
- A proper fraction = the numerator is smaller than the denominator.
45,808,001 ÷ 28,125,000 = 1, remainder = 17,683,001 ⇒
45,808,001 = 1 × 28,125,000 + 17,683,001 ⇒
45,808,001/28,125,000 =
(1 × 28,125,000 + 17,683,001) / 28,125,000 =
(1 × 28,125,000) / 28,125,000 + 17,683,001/28,125,000 =
1 + 17,683,001/28,125,000 =
1 17,683,001/28,125,000